Construction materials which consist of a flexible carrier coated or impregnated with a water-hardening reactive resin are already known. An example which may be mentioned is DE-A-2,357,931, which describes construction materials of flexible carriers, such as knitted fabrics, woven fabrics or non-wovens, which are coated or impregnated with water-hardening reactive resins, such as isocyanates or prepolymers modified by isocyanate groups. Carrier materials of glass fibres have been used to increase the strength of these construction materials (U.S. Pat. No. 4,502,479). However, these known carrier materials are only extensible in the transverse direction, but are virtually rigid in the longitudinal direction, in order thus to achieve a greater stability (U.S. Pat. No. 4,502,479, column 3, lines 45 to 47).
A disadvantage of the carrier materials which can be extended only in the transverse direction is the occurrence of folds when the material is applied to an uneven surface with conical elevations or variable radii, for example a human leg.
In U.S. Pat. No. 4,609,578, Raschel and tricot knitted fabrics of glass fibres which are processed in a certain manner of knitting are mentioned as carriers for construction materials. Apart from the transverse extension, these carriers have a longitudinal extension of at least 22 to 25%. The longitudinal extension of these knitted fabrics arises because of a certain type of laying during stitch formation and the high restoring force of the glass fibres (elasticity modulus 7000 to 9000 [daN/mm.sup.2 ]).
Construction materials based on glass fibres such as are described in U.S. Pat. No. 4,609,578 have the disadvantage of poor X-ray transparency. They also develop sharp edges at the points of break, leading to injuries. Another disadvantage is the occurrence of glass dust during preparation and removal of the construction material.
Construction materials such as are described in U.S. Pat. No. 4,609,578 cannot be prepared with fibres other than glass fibres. Fibres other than glass fibers have considerably lower elasticity moduli, so that carriers of comparable longitudinal and transverse extension are not obtained.